1. Field of the Invention
The present invention relates to an optical recording medium capable of making a high density record using a principle of a super-RENS.
2. Description of the Related Art
As a method for implementing an optical record of high density, a recording and reproducing technique referred to as a super-RENS (super-Resolution Near-field Structure) using near-field light has been known (for example, O plus E Vol.22, No.2 Pages.202 to 207, February, 2000). An optical disk (super-RENS disk) using a super-RENS method provides a readout layer in addition to a recording layer. The readout layer has properties in which reflectance becomes high at room temperature and transmittance becomes high at high temperature, and when a laser is applied, a fine opening with high transmittance is formed in a high temperature portion of the center of a laser spot. When near-field light occurring from this fine opening reaches a mark of the recording layer, the near-field light is converted into propagation light and a part of the light is reflected toward a pickup and information recorded in the recording layer as a mark is reproduced.
However, in such a super-RENS disk, a change in intensity of the reflected light according to the presence or absence of the mark of the recording layer, namely a degree of modulation is insufficient and in order to commercialize the super-RENS as an optical disk, it is necessary to improve the degree of modulation.